1. Field of the Invention
This invention relates to persistent switches for use in superconducting magnets. Such structures of this type, generally, provide a superconducting switch for a small, low cost magnet which is to be used for imaging human limbs.
2. Description of the Related Art
Many different kinds of superconducting switches have been built and used in superconducting magnets. The most common switch is made by winding long lengths of the superconductor with its original stabilizer (copper in many cases) and forming a switch which has a relatively high electrical resistance. Other switches with high resistance stabilizers such as supro nickel or stainless steel have been used in superconducting magnets. Known superconductive switches are joined to superconductive coils to help define superconducting magnets.
Exemplary of such switches with high resistance stabilizers is U.S. Pat. No. 5,093,645, entitled "Superconductive Switch for Conduction Cooled Superconductive Magnet" to Dorri et al. and assigned to the same assignee as the present invention. The switches with high resistance have the advantage of requiring shorter length, therefore will be smaller in size (fast recovery time for converting from normal to superconducting state) and, thus, are better suited for magnets with high inductance.
It is apparent from the above that there exists a need in the art for a superconducting switch which is compact through simplicity of parts and uniqueness of structure, and which at least equals the switching characteristics of the known superconducting switches particularly those as discussed in the above-identified Dorri et al. patent, but which at the same time is capable of being used in a small, low inductance magnet. It is a purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.